Quantum Vortex in a Spinor Bose-Einstein Condensate

Abstract

Quantum vortices in the multi-component Bose-Einstein condensation (BEC) are investigated theoretically. It is found that three kinds of the vortex configurations are possible and their physical properties are discussed in details, including the density distribution and the spin texture. By using the Bogoliubov theory extended to the three component BEC, the collective modes for these vortices are evaluated. The local vortex stability for these vortices are examined in light of the existence of the negative eigenvalue, yielding a narrow magnetization window for the local intrinsic stable region where the multi-components work together to stabilize a vortex in a self-organized way.

Mermin-Ho Vortex in Ferromagnetic Spinor Bose-Einstein Condensates

“…Ref. [15]) is stabilized in larger M/N and higher Ω region because in this vortex the dominant component φ 1 has the winding number 1, which can effectively lower the rotation energy.…”

“…There is a rich variety of topological defect structures, which are already predicted in the earlier studies [6,7] on the spinor BEC. These are followed by others [8,9,10,11,12,13,14,15,16] who examine these topological structures more closely, such as skyrmion, monopole, meron or axis-symmetric or non axis-symmetric vortices both for antiferromagnetic and ferromagnetic cases.Superfluid 3 He is analogous to the spinor BEC where the neutral Cooper pair possesses the orbital and spin degrees of freedom, thus the order parameter is a multi-component [17]. Among various topological structures, the Mermin-Ho (MH) [18] and Anderson-Toulouse (AT) [19] vortices of a coreless and non-singular l-vector texture are proposed in 3 He-A phase.…”

“…There is a rich variety of topological defect structures, which are already predicted in the earlier studies [6,7] on the spinor BEC. These are followed by others [8,9,10,11,12,13,14,15,16] who examine these topological structures more closely, such as skyrmion, monopole, meron or axis-symmetric or non axis-symmetric vortices both for antiferromagnetic and ferromagnetic cases.…”

“…We have performed extensive search to find a stable vortex, starting with possible vortex configurations, covering a wide range of the ferromagnetic interaction strength g s /g n = 0 ∼ −0.02 and examining various axis-symmetric and non-axis-symmetric vortices (see the classification of possible vortices in the axis-symmetric case [15,16]). We use the following parameters: the mass of a 87 Rb atom m=1.44×10 −25 kg, the trapping frequency ν r =200Hz, and the area density n z =2.0×10 3 /µm.…”

Raman coupling of Zeeman sublevels in an alkali-metal Bose-Einstein condensate

“…The work contained in this Article was motivated by an interest in creating and studying topological excitations of the spinor BEC such as coreless vortices [1,2]. Spin textures such as coreless vortices [3,4,5,6,7] and skyrmions [8,9] are important features of quantum many-body systems such as liquid helium [10,11], superconductors [12], and neutron stars [13], and they also possess important symmetry properties deeply connected to fundamental principles of physics [14].…”